Hello guys, my name is Joe. I am an auto mechanic from Nigeria. I under stand what ColinB is saying. In that case, you are actually opening the gearbox tank, changing or washing the oil filter, and draining all other old fluid left in there. That way, you will be needing 8.2liters. If not so, just to remove from the drainage nuzzle, you should need but 2.5 liters.
Thanks.